The present invention relates to a self-adhesive water proofing product which utilizes an adhesive layer comprising a bituminous component and a functionalized block copolymer component.
European Patent Application 0,238,149, published Sep. 23, 1987, discloses a bituminous composition which is useful as a self-adhesive compound. The composition comprises a bituminous component, a lithium salt of a C.sub.10-40 fatty acid or hydroxy fatty acid, an elastomer and an amorphous silica filler. This bituminous composition is described as being useful as a preformed self-adhesive layer on a protective sheet, such as roofing felt.
Prior systems, such as disclosed in European Patent Application 37,136, utilized compositions containing harder asphalts and thus were not sufficiently tacky for use in a self-adhesive product. When tackier asphalts were used, the formulation would generally exude oil which would often cause the product to lose adhesion to the substrate to which it was adhered. This phenomenon can be demonstrated in a laboratory flow resistance test at elevated temperatures. European Application 0,238,149 added the silica filler to the formation to prevent this phenomenon from taking place. However, this composition including silica has a disadvantage in that the use of too much silica can cause a loss of tack of the composition, thereby negating its usefulness as a preformed self-adhesive layer.
Therefore, it would be an advantage to provide a water proofing product which utilizes a bituminous self-adhesive layer which does not require the use of large amounts of silica to prevent oil from exuding from the bituminous composition (small amounts of silica may be advantageous herein). The present invention provides such a product.